Johansen, J. V., Manniche, C., & Kjaer, P. (2013). Vitamin D levels appear to be normal in Danish patients attending secondary care for low back pain and a weak positive correlation between serum level Vitamin D and Modic changes was demonstrated: A cross-sectional cohort study of consecutive patients with non-specific low back pain. BioMed Central.

Johansen, Jannick Vaaben, Claus Manniche, och Per Kjaer. Vitamin D Levels Appear to Be Normal in Danish Patients Attending Secondary Care for Low Back Pain and a Weak Positive Correlation between Serum Level Vitamin D and Modic Changes Was Demonstrated: A Cross-sectional Cohort Study of Consecutive Patients With Non-specific Low Back Pain. BioMed Central, 2013.

Johansen, Jannick Vaaben, Claus Manniche, och Per Kjaer. Vitamin D Levels Appear to Be Normal in Danish Patients Attending Secondary Care for Low Back Pain and a Weak Positive Correlation between Serum Level Vitamin D and Modic Changes Was Demonstrated: A Cross-sectional Cohort Study of Consecutive Patients With Non-specific Low Back Pain. BioMed Central, 2013.